过刊浏览

视顶盖神经元的两种振荡模式

蔡浩然, 李琳, 朱丹, 王红

北京大学第一医院中心实验室，北京100034；内蒙古医学院附属医院眼科，呼和浩特010050

摘要

本文旨在应用离体全细胞膜片钳技术，记录和分析爪蟾视顶盖神经元阈下振荡活动。长时程的去极化电流可以诱
发两种模式的阈下振荡，一种振荡是叠加在慢内向电流(slow inward current, SIC)之上的，另一种振荡则不伴有SIC。在本实
验中，去极化能诱发阈下振荡的细胞占所记录神经元的48%。振荡活动和SIC 都是河豚毒素耐受的，而在无钙溶液中浸泡的
脑片未记录到振荡和SIC。振荡活动的诱发依赖膜电位初始水平和变化幅度，只有当神经元的钳制电压从-40 mV 、-50 mV
或更低的初始水平去极化10 mV 时，才能诱发阈下振荡。SIC 的幅度和时程依赖于膜电位的初始水平。本文报导的阈下振荡
可能在蛙的生理和行为功能(如模式辨认，猎物识别和逃避行为等)方面起重要作用，进而也有可能在哺乳类和非哺乳类脊椎
动物的神经活动整合中发挥作用。

关键词： 阈下振荡; 慢内向电流; 去极化; 膜片钳; 视顶盖神经元; 非洲爪蟾

分类号：Q421；Q426；R338.8

Two oscillatory patterns induced by depolarization in tectal neurons of Xenopus

TSAI Hao-Jan, Li Lin, ZHU Dan, WANG HONG

Central Laboratory of the First Hospital, Peking University, Beijing 100034, China； Department of Ophthalmology of the First Hospital, Medical College of Inner Mongolia, Huhehaote 010050, China

Abstract

In the present study, we used in vitro whole-cell patch-clamp technique to record and analyze oscillatory activity of neurons
in the optic tectum of Xenopus. Two patterns of subthreshold oscillations were induced by long-term depolarizing current pulses. One
of the oscillating patterns occurred without a slow inward current (SIC); the other was superimposed on the SIC. The subthreshold
oscillations were induced by depolarization in 48% of the recorded neurons. Both the oscillations and the SIC were tetrodotoxin
(TTX)-resistant, but neither occurred when the slices were immersed in Ca2+ free solutions. The evocation of the oscillations was
voltage-sensitive: only when the initial membrane potentials of the neurons were held at -40 mV or -50 mV, 10 mV depolarization could
induce the subthreshold oscillations. The amplitude and duration of the SIC depended on the level of the initial membrane potential. The
subthreshold oscillations might play an important role in the physiological and behavioral functions of frogs, e.g. pattern discrimination,
prey recognition, avoiding behavior etc., furthermore, these oscillations might play roles in the integration of neural activity in both
mammals and non-mammalian vertebrates.

Key words: oscillations; slow inward current; depolarization; patch-clamp; tectal neurons; Xenopus

收稿日期：2008-08-04　　录用日期：2008-10-31

通讯作者：蔡浩然　　E-mail: hjtsai@bjmu.edu.cn

引用本文：

蔡浩然, 李琳, 朱丹, 王红. 视顶盖神经元的两种振荡模式[J]. 生理学报 2009; 61 (1): 85-93.

TSAI Hao-Jan, Li Lin, ZHU Dan, WANG HONG. Two oscillatory patterns induced by depolarization in tectal neurons of Xenopus. Acta Physiol Sin 2009; 61 (1): 85-93 (in Chinese with English abstract).